SU838707A1 - Noise measuring device - Google Patents

Description

one

This invention relates to instrumentation engineering and can be used in various fields of science and technology for measuring noise.

A sound meter is known, consisting of a connected MD-38 W type electrodynamic microphone, a microphone amplifier, a level switch with a two-section divider, frequency response correctors, a terminal amplifier with a smooth gain control, a quadratic rectifier and a switch instrument

The disadvantage of a sound level meter is the need for manual switching. the voltage dividers, due to the indicator arrow, rolls up or falls below the permissible level, which causes a certain error of the indicator when it is read by the operator. Besides; manual switching of voltage dividers distracts the operator’s attention,

The closest to the technical essence of the invention is a device for measuring noise, containing a sound meter, consisting of series-connected microwires, first voltage divider, first amplifier, type of work switch.

the corresponding contacts of which are connected to the frequency correction filters and the composite filters of the second voltage divider, the second amplifier of the rms detector and the L2 indicator. The disadvantage of this device is the low measurement accuracy.

The purpose of the invention is to increase the accuracy of measurements.

The goal is achieved by the fact that a device for measuring noise, containing a sound meter, consisting of series-connected microphones,

5 of the first voltage divider, the first amplifier, a switch of the type of work, the corresponding contacts of which are connected to the frequency correction filter and composite filters, the second voltage divider, the second amplifier of the RMS detector and the indicator, is equipped with two comparison circuits, a constant voltage source, trigger generator

5 pulses, a delay line, an AND circuit, and a switch, a decoder, a counter, and an OR circuit connected in series, with the output of the RMS noise level meter detector

0 is connected simultaneously to the first inputs of two comparison circuits, the second inputs of which are connected simultaneously to the output of the pulse generator and, through the delay line and the AND circuit to one of the inputs of the OR circuit, the other input of which is connected to the output of the second comparison circuit, the second input circuits. And through a trigger is connected to the outputs of the first comparison circuit, the outputs of the switch are connected to the corresponding voltage dividers, and the third inputs of the comparison circuits are connected to a constant voltage source. The drawing shows a structural diagram of the proposed device. The device contains a sound level meter 1, with a simple one. from the measuring microphone, the first voltage divider, the first amplifier, a sort of switch, the contacts of which are connected to the frequency correction filters and the composite filters, the second voltage divider, the second amplifier, the rms detector and the indicator. The output of the root-mean-square detector of the sound level meter 1 is simultaneously connected to the first inputs of the first and second comparison circuits 2 and 3, the second inputs of which are connected to the output of the generator 4 pulses, the output of which is connected to one input of the circuit I through the delay line 5, the other input of which is connected the trigger output 7, the output of the circuits And b is connected to one input of the circuit OR 8, the other input of which is connected to the output of the second comparison cxeNM 3, and the OUTPUT of the circuit OR 8 through the serially connected counter 9, the decoder 10 and the switch 11 are connected to the first and second m voltage divider same audio noise meter 1, the inputs of the third comparator scheme 2 and 3 are connected to a source of -12 constant voltage. The device works as follows. The signal under study is fed to the microphone of sound level meter 1, which is converted into an electrical signal, and, passing through the entire path, passes to the indicator of sound level meter 1. At the same time, the voltage divider of sound level meter 1 is in the state of maximum attenuation. The signals from the output of the average detector of sound meter 1 simultaneously arrive at the first inputs of the first and second comparison circuit 2 and 3. The third input of the first comparison circuit 2 receives a reference level from a constant voltage source 12, for example 840 which corresponds to O dB on the indicator scale sound level meter 1. When the condition is satisfied, 840 mV, i.e. when the input signal, which arrives at the first input of the comparison circuit 2, is less than the reference level that arrives at the third input of the first comparison circuit 2, then from its first output the signal goes to the first input of the trigger 7. The command to pass the signal goes to the second the input of the first comparison circuit 2 from the output of the 4-pulse generator. Having received permission to pass the signal from the first output of the first comparison circuit 2 to the first input of the trigger 7, the latter is transferred to the one state, and from the trigger output, the resolving potential to one input of the circuit 6 on the passage of the pulse that is fed to the other input from the output 4 pulse generator through line 5 delay. Line 5 of the delay serves to match the feed time to both inputs of the AND 6 circuit of the enable potential from the output of the trigger 7 and to the pulse from the generator 4 of the pulses through the delay line 5 taking into account the inertia of the first comparison circuit 2 and the trigger 7. The counter 9 is triggered by the pulse arriving from the output of the circuit AND 6 through the circuit OR 8. Counter 9 through the decoder 10 through the commutator 11 starts the transmission. Switch the corresponding divider of the sound level meter 1. The switching is performed until the signal above the reference level arrives at the first input of the first comparison circuit 2, and the condition oi is met. 840 mV. In this case, a ban is received from the first output of the first comparison circuit 2 and a signal is sent to the second input of the trigger 7 from its second output. The trigger 7 is transferred to the zero state and prevents the pulse from the circuit output Ib from passing, resulting in the counter 9 receiving the command to stop. The views of the counter and indicator of the sound level meter 1 determine the sound pressure level of the signal under investigation in decibels. In the case when the signal under study, coming from the output of the rms detector of sound level meter 1 and fed to the first input of the second comparison circuit 3, exceeds the level of the reference signal from the third output of the second comparison circuit 3 from the constant voltage source 12, , by-. radiating from the output of the 4-pulse generator, is set through the circuit, OR 8 of the counter 9 to the extreme position, which corresponds to the maximum attenuation value of the voltage divider of the sound level meter 1. The cycle repeats until the first input of the first reference circuit 2 is received level, while the counter 9 will receive a command to stop. The present invention significantly improves the accuracy of measurements.

Claims (2)

1.Il pike Yu.M. Measurement and rationing of production noise. Profizdat, 1964, p. 58-60. 2. Catalog of instrumental products of the Soyuzglavpribor nomenclature. Part 5. 0 M., 1972, p. 35 (prototype).